A major energy project linking Suffolk and Kent has taken a big step forward in selecting its converter station bidder.

National Grid announced it has picked Siemens Energy as its preferred bidder for Sea Link’s two high voltage direct current (HDVC) converter stations.

The proposed 138 kilometre connection, which would run from Pegwell Bay, in Ramsgate, to between Aldeburgh and Thorpeness, can now progress further as the two companies can begin the planning needed to deliver the project.

The majority of the cables for Sea Link will run under the sea, and it will carry renewable and low-carbon power to homes, businesses and public services.

The project will also involve new converter and substations being built on Minster Marshes.

Adrian Pierssene, Sea Link project director, said: “This is a major milestone for Sea Link – a vital part of Great Britain’s energy network, designed to meet rising demand and strengthen energy security.

“Siemens Energy, a leader in advanced energy technology, brings specialist expertise that will support the delivery of the infrastructure needed for the UK’s future energy network.”

Sea Link will run between the two counties through the converter stations, while the cables will be routed through the southern North Sea and across the Thames Estuary.

The project is seeking planning consent and if successful will enter its construction phase, expected to begin in 2027.

Mark Pilling, vice president of grid solutions Europe at Siemens Energy, said: “Sea Link is another crucial step in our efforts to meet the UK’s expanding electricity needs, delivering security of supply and reinforcing our grid – a key part of our energy transition.

“We’re looking forward to continuing our strong working relationship with National Grid.”

HDVC technology provides an efficient and reliable means of transmitting large amounts of power over long distances.

New land cables will link the converter stations at either end to the transmission network to make electricity available where it is needed.

Sea Link forms part of National Grid’s ‘The Great Grid Upgrade’ which aims to produce the volume and quality of infrastructure needed to increase capacity, as the nation’s demand for energy is set to double.

But the announcement has disappointed conservation charity Kent Wildlife Trust which has called the plans to build on the marshes an “environmental tragedy”.

Emma Waller, planning and policy officer for the charity, said: “It is deeply disappointing to see the celebration of potential contractors for the Sea Link project at this critical time, while the Planning Inspectorate is still considering the Development Consent Order.

“Announcing Siemens Energy as the preferred bidder for the converter stations may appear as a sign of progress, but it distracts from the harsh reality: building a converter station on Minster Marshes would be an environmental tragedy.

“Minster Marshes is a site of significant ecological value, home to vulnerable and protected wildlife that will be devastated by this development.

“The construction of this converter station would scar a precious natural landscape, fragment vital habitats, and threaten the survival of species that rely on the marshes to breed, feed and thrive.”

She added it was both “sad and frustrating” to witness economic interests being “prioritised over nature”, and pointed to alternative routes for Sea Link that exist the charity argues would avoid such destructive impacts.

“Nature cannot continue to pay the price for poor planning decisions, particularly in an era where we face dual climate and biodiversity crises,” she added.